Japanese Patent Application No. 1975-33044A discloses a foldup-type disposable diaper 201 as shown in FIG. 10 of the accompanying drawings. This diaper 201 is composed of a liquid-absorbent pad, a liquid-pervious inner sheet 222 and a liquid-impervious outer sheet 223 so as to present a rectangle and this rectangle is then folded along a transversal 210a orthogonal to long sides of the rectangle in two halves in a longitudinal direction. Simultaneously, the rectangle is tucked from its transversely opposite edges inwardly of the diaper, more specifically, toward a middle point of the transversal 210a so as to form pockets 218. This diaper is adapted to be worn in combination with use of a diaper cover and surface sections of the sheet 223 facing each other as the rectangle is tucked inward in this manner are partially bonded to each other in order to prevent the respective pockets 218 might get out of initial shapes thereof even after the diaper has been developed to put the diaper on a wearer's body. The diaper arranged in such a manner is effective to avoid leakage of bodily discharges regardless of its rectangular shape because a region of the diaper intended to cover the wearer's crotch is sufficiently narrow to be placed closely against the wearer's crotch.
Japanese Utility Model Application No. 1972-36734A discloses a foldup-type diaper made from a rectangular strip. This diaper also is adapted to be worn in combination with use of a diaper cover and the diaper is tucked inward from its transversely opposite edges in a longitudinally middle zone of the diaper. The crotch region of the diaper obtained in this manner has its width sufficiently reduced to be placed closely against the wearer's crotch and thereby to alleviate an anxiety of sideways urine leakage.
Both of the above-cited conventional diapers are of the rectangular open-type and adapted to be put on an infant's body by flatly developing the diaper and applying this to the hip of the infant lying on his or her back. However, it is likely that the regions of the diaper having previously been folded and tucked might get out of initial shapes thereof as the diaper is flattened and the function of these regions might be insufficient after the diaper has been put on the wearer's body. The diaper disclosed in Japanese Patent Application No. 1975-33044A intends to prevent the diaper from getting out of its initial shape by partially bonding together the surface sections opposed to each other as the diaper is folded and tucked. However, such bonding may obstruct the diaper to be flatly developed and retard operation of putting the diaper on the wearer's body. The diaper disclosed in the above-cited Japanese Utility Model Application No. 1972-36734A is accompanied with an inconvenience that the crotch region folded and tucked in this manner may get out of its desired shape as the diaper is flatly unfolded.